WO2023224235A1

WO2023224235A1 - Static electrcity control device for semiconductor processing system

Info

Publication number: WO2023224235A1
Application number: PCT/KR2023/003460
Authority: WO
Inventors: 박흥균
Original assignee: (주)넥스틴
Priority date: 2022-05-20
Filing date: 2023-03-15
Publication date: 2023-11-23
Also published as: TW202412057A

Abstract

A static electricity control device for injecting static electricity into a substrate disposed in a vacuum chamber or removing static electricity formed on the substrate in a semiconductor processing system, according to an embodiment, comprises: a charged particle generation unit, disposed on an upper side inside the vacuum chamber, that generates charged particles including positive ions and electrons by generating a vacuum ultraviolet ray (VUV) and reacting the VUV with a process gas inside the vacuum chamber; a grid provided with a plurality of holes, disposed on a lower side of the charged particle generation unit, that selectively pass the type of charged particles downward according to an input voltage; a substrate support, disposed below the grid and having the substrate positioned thereon, that is made of a conductive material and guides the charged particles passing through the grid toward the substrate at a predetermined density according to an input bias voltage; and a static electricity control unit that controls the static electricity of the substrate by supplying a pulsed voltage to at least one of the grid and the substrate support, wherein the grid and the substrate support are arranged so as to have a separation distance that is within four times the mean free path of the process gas according to environmental conditions of the vacuum chamber.

Description

Electrostatic control devices in semiconductor processing systems

This technology is generally related to a technology that can easily adjust the level of static electricity required by the substrate according to the semiconductor process by injecting static electricity onto the substrate or removing static electricity formed on the substrate.

Recently, as the integration of the semiconductor industry increases, the size and area of semiconductor devices tend to decrease.

Accordingly, the size of the pattern forming the pattern of the semiconductor device and the thickness of the thin film are decreasing, and in particular, factors that did not have a significant influence in the past are emerging as important factors in the development of semiconductor devices. One of these factors is static electricity formed on the substrate, and a process to control the static electricity formed on the substrate is being applied.

During the semiconductor process, static electricity is formed on the substrate during deposition, etching, or substrate cleaning processes using plasma. If the voltage is too high or the substrate is suddenly discharged after charging, it can cause pattern deformation due to phenomena such as arcs. This can happen.

In addition, the static electricity formed on the substrate is mainly generated by charges during processes using deionized water, charge transfer from charged plastic materials, or induction charging or plasma.

To prevent the generation of such static electricity, positive charges (ions) or negative charges (electrons) are pre-charged (injected) into the insulator (thin film) of the substrate from several nanometers to tens of nanometers before the pattern formation process, cleaning process, or plasma treatment process. ), it is used to control fine patterns such as local pattern uniformity and local edge placement errors during the multiple patterning process, and to control (trade-off) static electricity generated during other processes. This is called an electrostatic charger.

Meanwhile, static electricity on the substrate is mainly generated during the photo process or cleaning process using rotational movement, and it is known that the most static electricity is concentrated in the center due to the difference in centrifugal force. In other words, due to the high-speed rotation of the wafer in the photo resist coating process, the concentration of air flow in the center of the substrate increases by more than three times compared to the outside, and static electricity is formed around the center where centrifugal force is relatively weak. Static electricity caused by a strong electric field formed in the center of the substrate is charged to the inside of the multilayer insulating film or to the surface of the wafer and the photoresist pattern formed on the surface.

Accordingly, a method for efficiently removing static electricity formed on a substrate is needed, and a device that removes static electricity already generated on the substrate or generated during the process is called a static electricity discharger.

Figure 1 (A) illustrates a shape in which electrostatic voltages of -50V, -30V, and -10V appear from the central part of the substrate 1 to the outer side.

However, as shown in FIG. 1(A), when charged with a high voltage around the center of the substrate 1, the area corresponding to the center of the substrate in FIG. 1(B) (static electricity in FIG. 1(A) In the area where the voltage is -50V, charges are charged not only on the surface of the substrate (1) such as insulating P/R (Photo Resist) or oxide, but also to a certain depth (D) of the substrate surface, resulting in neutralization by ions with low kinetic energy. An impossible situation may occur.

Additionally, the electrostatic voltage charged to the substrate has many variables, such as the type of process, material, and pattern shape, and is generally between -100V and +100V.

For example, as shown in FIG. 1(B), charging of 100V or less is applied to the substrate 1 on which an insulating film in a fine circuit of less than 10 nm or a pattern P having an aspect ratio of "5" or more is formed. A voltage is formed, but because the pattern width is narrow, it is difficult to remove static electricity accumulated inside the thin film due to the self-neutralizing effect between positive and negative ions generated in the ionizer and the reduction of ion collisions due to the low electromotive force due to the low voltage difference between the substrate and ions. there is.

Conventionally, static electricity from the substrate was removed using an ionizer. However, in the method using an ionizer, as shown in FIG. 2, when static electricity is charged to the substrate at 1000V, reducing it to within 100V with a soft Xray ionizer requires a decay time of 1 to 2 seconds. However, when a charging voltage of 100 V or less is initially formed, it takes a long time to reduce the charging voltage to that level.

In addition, considering that the ion density of the ionizer is generally 10 ⁶ , if charging also occurs inside the silicon oxide layer below the PR in the substrate and the ion density becomes 10 ⁸ or more, a conventional ionizer is used to irradiate the substrate (1). ) cannot be removed.

One of the problems to be solved with this technology is to solve the difficulties of the prior art described above. One of the challenges to be solved with this technology is to create a semiconductor processing system that can accurately and quickly inject static electricity onto a substrate or easily remove static electricity formed on the substrate using a simple method of controlling the voltage applied to the grid and substrate support. The purpose is to provide a static electricity control device.

The static electricity control device of the semiconductor processing system according to this embodiment is a static electricity control device of the semiconductor processing system that injects static electricity onto a substrate disposed in a vacuum chamber or removes static electricity formed on the substrate, and is disposed on the upper side of the vacuum chamber. , a charged particle generation unit that generates charged particles including positive ions and electrons by generating VUV (Vacuum Ultraviolet Ray) and reacting this VUV with the process gas inside the vacuum chamber, and is disposed below the charged particle generation unit to input A grid provided with a plurality of holes that selectively allow charged particles to pass downward according to voltage, the substrate is placed on the lower side of the grid, and the charged particles passing through the grid according to the input bias voltage are preset. It includes a substrate support that induces density toward the substrate, and a static electricity control control unit that supplies a voltage in the form of a pulse to at least one of the grid and the substrate support to control static electricity of the substrate, wherein the grid and the substrate support depend on environmental conditions of the vacuum chamber. It is arranged to have a separation distance of less than 4 times the free stroke distance of the process gas.

In one aspect of this embodiment, the static electricity control unit applies the bias voltage applied to the substrate support to be higher than the voltage applied to the grid in the static electricity injection mode, and applies the voltage applied to the grid in the static electricity removal mode. Apply the bias voltage applied to the substrate support so that it is within a similar preset range.

In one aspect of this embodiment, the electrostatic control control unit adjusts the voltage level by adjusting the pulse period applied to the grid and fingerboard support.

In one aspect of this embodiment, the charged particle generator includes one or more VUV lamps that emit VUV.

In one aspect of this embodiment, a beam generator is further provided below the VUV lamp to emit an ion beam in the form of a line through the side of the vacuum chamber, so that charged particles, ion beams, and the process are generated by the reaction of the VUV and the process gas. Charged particles are simultaneously generated through gas reaction to increase charged particle density.

In one aspect of the present embodiment, the charged particle generator includes a plasma generator that generates plasma, and a separator that transmits only VUV below the plasma generator, and the charged particle generation unit generates charged particles by a reaction between the VUV generated in the plasma generator and the process gas. creates .

In one aspect of this embodiment, the plasma generator includes at least one micro plasma device that generates plasma using a power source in the range of 10 to 200 W in a vacuum environment where the volume of the vacuum chamber is in the range of 500 to 1000 cc.

In one aspect of this embodiment, the static electricity control unit adjusts the static electricity of the substrate by controlling at least one of the type of process gas injected into the vacuum chamber of the micro plasma device or the plasma power source.

In one aspect of this embodiment, the plasma generator includes a plurality of micro plasma devices, and the electrostatic control control unit individually controls the type of process gas or plasma power injected into the vacuum chamber of each micro plasma device to control the plasma power of the substrate. Control static electricity.

In one aspect of this embodiment, the plasma generator includes a plurality of micro plasma devices, the separation plate is disposed in a one-to-one correspondence with each micro plasma device, and the static electricity adjustment control unit controls the vacuum chamber of each micro plasma device. The static electricity of the substrate is adjusted by individually controlling the type of process gas injected or the plasma power, and each separator plate includes lenses having different divergence angles.

In one aspect of this embodiment, the grid and the substrate support are of a multi-zone type in which multiple areas are electrically separated, and the static electricity control unit individually supplies voltages at different levels to each region of the grid and the substrate support.

In one aspect of this embodiment, the static electricity control unit supplies voltage to each area of the grid and the substrate support to inject static electricity into a certain portion of the substrate and remove static electricity from another portion of the substrate.

In one aspect of this embodiment, the grid includes an upper grid and a lower grid disposed below the upper grid, and the static electricity adjustment control unit supplies voltages at different levels to the upper grid and the lower grid.

In one aspect of this embodiment, the diameter of the hole formed in the lower grid is set to be different from the diameter of the hole formed in the upper grid, and the electrostatic control control unit applies a negative voltage of the first level to the lower grid to create a gap between the lower grid and the substrate. After guiding ions to the upper grid through the holes in the lower grid, a negative voltage greater than the first level is applied to the upper grid so that the ions introduced through the lower grid collide with the lower surface of the upper grid to generate secondary electrons. It is controlled to emit higher density electrons toward the substrate through the holes in the lower grid.

In one aspect of this embodiment, the hole opening ratio in the center of the grid is formed to be higher than the hole opening ratio in the peripheral area.

In one aspect of the present embodiment, the grid and the substrate support are further provided with a distance adjusting unit that moves up and down within the vacuum chamber, and the static electricity adjusting control unit adjusts the distance based on the process gas free stroke distance calculated according to the environmental conditions of the vacuum chamber. The distance adjustment unit is controlled to change the position of at least one of the grid or the substrate support to the upper or lower side.

In one aspect of this embodiment, the surface of the grid is coated or sputtered with a film containing carbon components including carbon, CNT, and glassy carbon to prevent arc generation.

In one aspect of this embodiment, the grid surface is coated or sputtered with one of silicon oxide (SiO2), aluminum oxide (Al2O3), silicon nitride (Si3N4), and an oxide-based thin film to prevent arc generation.

The present technology provides the advantage of being able to accurately and quickly inject static electricity onto a substrate or easily remove static electricity formed on the substrate. Therefore, it is possible to minimize the defect rate due to the semiconductor manufacturing process and to manufacture more reliable semiconductor devices.

1 is a diagram to explain the problem of removing static electricity in a semiconductor.

Figure 2 is a diagram for explaining the static electricity removal characteristics of the natural drop method using an ionizer.

FIG. 3 is a diagram schematically showing a semiconductor processing system equipped with a static electricity control device according to the first embodiment.

FIG. 4 is a diagram illustrating the configuration of the charged particle generation unit illustrated in FIG. 3.

FIG. 5 is a diagram for explaining the multi-zone structure of the grid and substrate support illustrated in FIG. 3.

FIG. 6 is a diagram for explaining the dual grid structure of the grid illustrated in FIG. 3.

FIG. 7 is a diagram showing the results of electrostatic injection and static electricity removal experiments according to the distance between the grid illustrated in FIG. 3 and the substrate support.

FIG. 8 is a diagram for explaining the operation of the static electricity control device of the semiconductor processing system illustrated in FIG. 3.

The embodiments described in the present invention and the configurations shown in the drawings are only preferred embodiments of the present invention and do not express the entire technical idea of the present invention. Therefore, the scope of rights of the present invention is limited to the embodiments and drawings described in the text. It should not be construed as limited by. In other words, since the embodiments can be modified in various ways and can have various forms, the scope of rights of the present invention should be understood to include equivalents that can realize the technical idea. In addition, the purpose or effect presented in the present invention does not mean that a specific embodiment must include all or only such effects, so the scope of the present invention should not be understood as limited thereby.

All terms used herein, unless otherwise defined, have the same meaning as commonly understood by a person of ordinary skill in the field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as consistent with the meaning in the context of the related technology, and cannot be interpreted as having an ideal or excessively formal meaning that is not clearly defined in the present invention.

Figure 3 is a diagram schematically showing a semiconductor processing system equipped with a static electricity control device according to a first embodiment of the present invention.

Referring to FIG. 3, in the semiconductor processing system according to the present invention, the charged particle generation unit 100 is disposed on the inside upper side of the vacuum chamber C where the substrate 10 is placed, and the charged particle generation unit 100 The grid 200 and the substrate support 300 are sequentially arranged on the lower side, and charged particles are generated in the vacuum chamber (C) through the charged particle generator 100 and applied to the grid 200 and the substrate support 300. Static electricity that is controlled to inject static electricity onto the substrate 10 or remove static electricity formed on the substrate 10 by controlling the density of charged particles emitted toward the substrate 10 through the grid 200. Includes an adjustment control unit 400.

In addition, the distance between the grid 200 and the substrate support 300 is adjusted up and down by adjusting the position of at least one of the grid 200 and the substrate support 300 according to the control of the electrostatic control control unit 400. It may further include an adjustment unit 500.

That is, in this embodiment, charged particles generated in the vacuum chamber (C) are selectively transmitted through the grid 200, and a bias voltage is applied to the substrate support 300 that supports the substrate 10 to form the grid 200. The charged particles that have passed through are guided toward the substrate 10 to inject static electricity into the substrate 10 or to neutralize (remove) the static electricity formed on the substrate 10.

Next, this embodiment will be described in more detail.

The vacuum chamber (C) is equipment that performs a semiconductor process on the substrate 10. Although not shown, it includes a vacuum forming part to maintain the inside of the chamber in a vacuum state and a gas supply part to supply gas into the chamber. do.

At this time, the vacuum forming unit may include a vacuum pump that discharges the material inside the chamber to the outside of the chamber, a vacuum gauge that can detect the degree of internal vacuum, a valve that controls the inflow and outflow of materials, and piping connecting each component. You can. And, the vacuum forming unit preferably maintains the degree of vacuum inside the chamber at 10 ^-1 to 10 ^-4 Torr.

The gas supply unit can supply different gases depending on the process, and can provide gases such as helium (He), nitrogen (N2), and argon (Ar) into the chamber, and the flow rate of the gas is It can be set from 10 to 1000 sccm.

The charged particle generator 100 is a device that generates VUV (Vacuum Ultraviolet Ray) and reacts the VUV with a process gas to generate charged particles containing positive ions and electrons. The charged particle generator 100 includes at least one of a VUV lamp and a plasma generator, and can additionally generate a line-shaped ion beam or a large-area electron beam using plasma to generate charged particles containing electrons and ions. .

Figure 4 illustrates the configuration of the charged particle generator 100.

As shown in FIG. 4 (A), the charged particle generation unit 100 may have a VUV lamp 110 located on the upper side of the vacuum chamber (C), and a large area from the side of the vacuum chamber (C) below the VUV lamp 110. A beam generator 120 that emits a beam (B), that is, an ion beam or an electron beam, into the vacuum chamber (C) may be additionally provided. At this time, the VUV lamp 110 may be arranged in plural numbers. That is, the VUV lamp 110 generates and irradiates VUV light in the 110nm to 400nm wavelength band into the vacuum chamber (C). VUV reacts with the process gas inside the vacuum chamber (C), decomposes the gas particles, and generates charged particles containing positive ions and electrons.

The beam generator 120 dissociates the process gas inside the vacuum chamber C through an ion beam or an electron beam to generate additional positive ions and electrons, thereby further increasing the density of electrons and positive ions emitted toward the grid 200. Here, the configuration of the beam generator 120 that generates a line-shaped beam is disclosed in Korean Patent Nos. 10-1911542, 10-1989847, 10-1998774, and 10-2118604, which are patents of the inventor of the present application. All of which is included in this application, and detailed description thereof will be omitted.

In addition, the charged particle generator 100 includes a plasma generator 130 disposed inside the vacuum chamber (C), as shown in FIG. 4(B). The plasma generator 130 may generate charged particles including positive ions and electrons by reacting VUV formed in plasma with a process gas.

On the lower side of the plasma generator 130, a VUV lamp 140 may be additionally disposed to emit VUV into the vacuum chamber (C) from the side of the vacuum chamber (C). At this time, a plurality of VUV lamps 140 may be disposed, and may be located on both sides of the vacuum chamber (C), respectively, as shown in FIG. 4(B).

Electrons excited in the plasma formed in the plasma generator 130 return to the ground state and emit light having energy corresponding to the energy difference between the excited state and the ground state to the outside. The wavelength band of light formed in this way is an ultraviolet band that can dissociate the gas provided by the gas supply unit to form particles with a negative charge and/or particles with a positive charge.

The plasma generator 130 may be an inductively coupled plasma (ICP) generating device or a capacitively coupled plasma (CCP) generating device. The electrical signal supplied to the plasma generator 130 may be a pulse or continuous wave (CW). For example, the ultraviolet ray band includes near ultraviolet rays (NEAR UV, 300 nm to 380 nm), far ultraviolet rays (FAR UV, 200 nm to 300 nm), and vacuum ultraviolet rays (VUV, 70 nm to 70 nm) that have a shorter wavelength than the far ultraviolet band. 200 nm), and in the present invention, the plasma generator 130 can form ultraviolet rays in the vacuum ultraviolet (VUV) band.

The plasma generator 130 may be a micro-plasma source that generates plasma using DC, RF, and pulse power in the range of 10-200 W in an environment where the volume of the vacuum chamber is in the range of 500-1000 cc. The micro-plasma source is It is equipped with a separate vacuum chamber for forming plasma, and is provided with means for performing gas injection, gas exhaust processing, vacuum processing, and power supply processing into this vacuum chamber under the control of the static electricity control control unit 400. .

At this time, the micro plasma source consists of one of the atmospheric pressure plasma devices using ICP, CCP, TCP, hollow cathode, and DBD, and generates plasma using various process gases including oxygen, nitrogen, argon, and helium.

Compared to VUV lamps, which typically require a preheating time of about 30 seconds and cannot control the output of the light source, the micro plasma source has a vacuum chamber volume in the range of 500 to 1000 CC, so the plasma can be turned on/off freely and process conditions can be easily changed. It has the advantage of having a short plasma turn on time. When using a microplasma source, it takes more processing time than necessary for the semiconductor multilayer thin film, so it is possible to prevent deterioration of thin film properties and to more quickly and adaptively inject or remove static electricity on the substrate.

Additionally, in the present invention, as shown in FIG. 4(C), the plasma generator 130 can be configured with a plurality of micro plasma sources. Figure 4(C) illustrates the first to third

micro plasma sources

131, 132, and 133.

In the embodiment illustrated in Figure 4 (C), the first to third

micro plasma sources

131, 132, and 133 are each implemented on independent vacuum chambers, and the static electricity adjustment control unit 400 operates on the first to third

micro plasma sources

131, 132, and 133. ) can be configured to individually control the vacuum environment, process gas type, plasma power, etc. to perform different static electricity injection or static electricity removal treatments in different areas of the substrate 10.

That is, when more static electricity is formed in the center than in the peripheral part of the substrate 10, the static electricity adjustment control unit 400 sets the pressure or power of the micro plasma source corresponding to that location differently from the pressure or power of the micro plasma source at other locations. You can set it. This allows a more precise static electricity control process to be performed compared to VUV lamps, which cannot control the wavelength of the output VUV light.

In addition, the wavelength of VUV generated from the micro plasma source depends on the type of process gas. When helium gas is used as the process gas, the main wavelength is 58.4 nm, when oxygen gas is used as the process gas, the main wavelength is 130.5 nm, and when argon gas is used, the main wavelength is 58.4 nm. When used as a process gas, it is 104.8nm. Accordingly, the static electricity adjustment control unit 400 can select a desired VUV wavelength by varying or mixing the types of process gases supplied to the vacuum chambers of the first to third

micro plasma sources

131, 132, and 133, and through this, the desired VUV wavelength can be selected on the substrate 10. The level of static electricity injected or removed can be set differently for each area. For example, when the band gap energy of the semiconductor thin film formed on the substrate 10 is large, helium gas can be used, and when the band gap energy is small, nitrogen gas can be used.

Additionally, the static electricity control control unit 400 can selectively operate only the micro plasma source at a location corresponding to the area of the substrate 10 that requires static electricity control.

In addition, depending on the usage environment including the type of substrate subject to static electricity control, the first to third

micro plasma sources

131, 132, and 133 may be implemented as different types of atmospheric pressure plasma devices using ICP, CCP, TCP, hollow cathode, and DBD. .

Meanwhile, in order to use the VUV wavelength formed in the plasma, a separator plate 150 made of MgF2 glass or _CaF2 glass is placed on the lower side of the plasma generator 130 as shown in FIG. 4(B) to generate the VUV wavelength generated in the plasma generator 130. It can be configured to block positive ions, electrons, and active species from being emitted downward and to transmit only VUV. At this time, charged particles generated by the reaction of the VUV generated from the plasma generator 130 and the process gas and charged particles generated by the reaction of the VUV and the process gas emitted from the VUV lamp are simultaneously generated.

The separation plate 150 may be further equipped with an optical filter coating that selectively transmits only VUV to emit light of 10 to 20 mm in size downward, and may be used as a concave lens or convex lens. The divergence angle of the VUV light emitted downward can be set to a desired shape using the light. When implementing the separator plate 150 in the embodiment illustrated in FIG. 4 (C), the separator plate 150 may be disposed (151, 152, 153) below the first to third micro plasma sources (131, 132, and 133), respectively, They can have different divergence angles. For example, a convex lens may be provided below the first and third

micro plasma sources

131 and 133, and a concave lens may be provided below the second micro plasma source 132. Of course, as in the embodiment illustrated in FIG. 4(B), it is also possible to provide lenses with different divergence angles corresponding to each microplasma source on one separator plate 150.

Additionally, a light diffusion plate (not shown) can be placed on the front of the VUV lamp 140 to diffuse the VUV light into the vacuum chamber (C).

Meanwhile, the grid 200 is composed of a plate shape made of a conductive material, and a plurality of micro holes are formed to discharge charged particles flowing in from the upper side to the lower side. Considering that the electrostatic charging voltage of the substrate 10 is always formed to be higher at the center than the outside after the process, it is preferable that the microhole opening ratio at the center of the grid 200 be formed at least 10% higher than the surrounding area, and the microholes are The diameter can be set in the range of 1 to 10 mm in shapes such as circles and diamonds.

The grid 200 selectively emits charged particles toward the substrate 10 according to the voltage supplied through the static electricity adjustment control unit 400.

In addition, as illustrated in FIG. 5, the grid 200 is composed of a multi-zone type in which a plurality of areas are electrically separated, and different voltages (V ₁ , V ₂ , V ₃ ) are individually supplied to each area. It can be configured to be supplied as. At this time, considering that the center of the substrate 10 has a higher electrostatic voltage than the outside, the voltage supplied to the center of the grid 200 can be set higher than that of the surrounding area (V ₁ >V ₂ >V ₃ ). That is, a higher density of charged particles can be supplied to the center of the substrate 10.

The multi-zone type grid 200 prepares a circular or square graphite or metal plate with a thickness of 5 mm to 10 mm separated into multi zones, and polyimide of 50 μm to 100 μm. A copper (Cu) film of 20 to 100 μm is laminated to a metal plate or graphite. Next, the copper (Cu) film is patterned on both sides and then etched, and the metal plate or graphite is patterned to be electrically separated. Then, a number of holes are formed to have a diameter of 1 to 10 mm, and the insides of the holes are plated. At this time, it is desirable for the hole to have an opening ratio of 50% or more of the metal plate or graphite surface, and the inside of the hole can be treated with 20 μm electroless plating and 30 μm electrolytic plating.

In addition, the grid 200 is a film containing carbon components including carbon, CNT, glassy carbon, etc. on the upper surface, but it is also made of a film containing carbon components such as DLC (diamond like carbon), silicon oxide (SiO ₂ ), and aluminum oxide (Al ₂ It can be configured to prevent arc generation by coating or sputtering one of O ₃ ), silicon nitride (Si ₃ N ₄ ), or oxide-based thin films to a thickness of 100 to 1000 nm. . From this, the pattern deformation of the ultra-fine pattern of several nm in size formed on the substrate 10 due to the arc occurring on the surface of the grid 200 due to the partial concentration phenomenon due to the problem of concentration of ions and electrons on the upper part of the grid 200 ( It is possible to prevent problems such as distortion, pattern shrinkage, and line edge roughness (LER).

Additionally, the grid 200 may have a dual grid structure consisting of an upper grid 210 and a lower grid 220, as shown in FIG. 6 . At this time, the upper grid 210 and the lower grid 220 are provided with different voltages (Vg ₁ and Vg ₂ ) from the static electricity adjustment control unit 400, respectively. That is, the upper grid 210 is provided with a voltage of, for example, 50-100 V, sufficient to induce the charges inside the vacuum chamber (C) into the grid hole, and the lower grid 220 is provided with a voltage that enters the grid hole. A voltage of 300 to 500 V is provided to have sufficient kinetic energy to be released to the substrate.

In the dual grid structure, when the charge between the charged particle generator 100 and the grid 200 collides with the surface of the grid 200, it is guided to the grid hole by the low voltage of the upper grid 210, so that ARC, etc., is generated at the top of the grid. This phenomenon can be prevented from occurring. In addition, charges can be distributed more widely through the holes in the upper grid 210 and the lower grid 220 that are spaced apart by a certain distance (d _g ), thereby increasing the uniformity of charges discharged to the substrate 10.

In addition, the grid 200 of the dual grid structure sets the grid hole diameter of the lower grid 220 to be 10 to 20% smaller than the grid hole diameter of the upper grid 210, thereby additionally generating secondary electrons within the grid 200. By doing so, the charge density discharged toward the substrate 10 can be made higher.

That is, the upper grid 210 serves as a cathode that emits secondary electrons, and is made of materials such as aluminum or anodized Al, Carbon, CNT, etc., and applies a negative voltage of -50 to -150 V to the lower grid 220. When this is applied, the ions formed between the lower grid 220 and the substrate 10 are provided to the upper grid 210, and a larger negative voltage, for example, a voltage of -200 to -1000 V, is applied to the upper grid 210. When this happens, these ions can collide with the lower surface of the upper grid (cathode) and generate secondary electrons. Accordingly, electrons of about 10 ³ cm ² formed between the lower grid 220 and the substrate 10 by VUV and secondary electrons additionally generated inside the grid 200 are simultaneously emitted toward the substrate 10, thereby The electron density applied to the (10) side increases to 10 ⁶ ~ 10 ⁸ cm ² , resulting in increased process efficiency.

As shown in FIG. 6(B), the lower surface of the upper grid 210 can be roughened to make the direction of movement of secondary electrons wider and improve uniformity. Since the generation of secondary electrons through this dual grid structure does not generate active species (radicals) with chemical properties, a process that does not damage the substrate 10 is possible. In particular, the electron beam can inject a high density of electrons into a specific area in a short period of time when injecting static electricity, thereby minimizing the physical impact of the substrate 10.

Meanwhile, the substrate support 300 is composed of a plate shape made of a dielectric material or a conductive material, so that charges emitted from the grid 200 according to the bias voltage supplied from the static electricity adjustment control unit 400 are stored on the substrate 10 at a preset density. Gives kinetic energy to go to the side.

At this time, the substrate support 300 may be divided into a plurality of regions and configured to individually provide different bias voltages from the static electricity adjustment control unit 400. For example, as shown in FIG. 5, when the areas of the grid 200 are divided and each area is individually supplied with voltage, the substrate support 300 is divided into the same area as the grid 200 and receives the voltage of the grid 200. Each region can receive a bias voltage with the same polarity and equal voltage difference. Additionally, only the grid 200 may be separated into multiple areas, and the substrate support 200 may not be separated into multiple areas, and the grid 200 and the substrate support 200 may be separated to have areas of different shapes. When the static electricity control level for each region is different, the voltage difference between the voltages applied to the grid 200 and the substrate support 300 may be different for each region. Accordingly, static electricity injection and static electricity removal processes can be performed simultaneously in different areas of the substrate 10.

In addition, a rotating part 310 may be additionally provided on the lower side of the substrate support 300 to rotate the substrate support 300, and the rotating part 310 may be used during the static electricity control process under the control of the static electricity control control unit 400. Rotate the substrate support 300 at 1 to 30 RPM.

Additionally, in this embodiment, the distance between the grid 200 and the substrate 10 is preferably set to within 4 times the free stroke distance of the process gas according to the environmental conditions inside the vacuum chamber (C).

At this time, the process gas free stroke distance (λ) can be calculated using Equation 1 below.

Here, K is Boltmann's constant, T is temperature, P is pressure, and D is the process gas particle diameter.

As a result of the present inventor performing an electrostatic charging experiment using a 300 mm silicon wafer using a turbo vacuum pump in the chamber size of a general semiconductor manufacturing equipment, 330 mm (diameter) ), if the distance between them is placed beyond a certain free stroke distance (10 mm) and bias power is not supplied to the

substrate support

300, 300 mm silicon. Process conditions when using a SiO ₂ 100 nm deposited wafer: pressure 30 mtorr, 5 sccm, distance between substrate and grid 100 mm, grid voltage + 250 V. The voltage of the substrate 10 after 30 seconds under process conditions is expected to be + 80 volts. It was found that there was a significant difference from -10V.

On the other hand, under the same process conditions as above, the distance between the substrate 10 and the grid 200 is set to 10 mm, which is the free stroke distance depending on the process gas and pressure, and a bias voltage of 200V is supplied to the substrate 10. , the substrate 10 voltage was induced to the desired -10 V. Through this, it was confirmed that the distance between the substrate 10 and the grid 200 and the bias voltage to the substrate support 300 are important variables in controlling static electricity on the substrate 10.

In addition, as shown in FIG. 7, even when the distance between the grid 200 and the substrate 10 is increased to 40 mm, which is 4 times the free stroke distance (10 mm) according to the process gas environment, the static electricity injection and removal efficiency remains within a certain range. It was confirmed that it appeared satisfactorily. In FIG. 7 (A) is the result of an experiment on the electrostatic injection process, measured using the QC 3000e system of Semilab. As a result, the distance between the grid 200 and the substrate 10 under the above-described process gas conditions is determined by the process gas environment. It was confirmed that the same electrostatic voltage was maintained on the substrate 10 up to 40 mm, which is 4 times the free stroke distance (10 mm).

In FIG. 7 (B) is the result of an experiment on the static electricity removal process, measured using the QC 3000e system of Semilab, and as a result, the distance between the grid 200 and the substrate 10 under the above-described process gas conditions is depending on the process gas environment. Up to 40 mm, which is four times the free stroke distance (10 mm), static electricity is removed and the static electricity voltage converges to "0", but it can be seen that static electricity is generated again at distances beyond that.

This means that the static electricity injection and removal efficiency according to the free path distance of electrons and cations is determined by the difference in the size of molecules compared to the process gas, or selective electron or cation extraction at the top of the grid where ions and electrons are formed by grid voltage, and substrate. It was confirmed to be influenced by the bias electric field of the support and the rapid vacuum evacuation effect.

Meanwhile, the static electricity control unit 400 controls the voltage supplied to each device so that ions or electrons are supplied to the substrate 10 at a desired density to inject static electricity onto the substrate or to remove static electricity formed on the substrate 10. Control to remove. The electrostatic control control unit 400 adjusts the power level by adjusting the pulse period when power is supplied to the grid 200 and the substrate support 300.

In the electrostatic injection mode, the electrostatic control control unit 400 supplies voltage so that the voltage difference between the grid 200 and the substrate support 300 is 2 times or more, for example, 2.5 times or more. That is, the bias voltage applied to the substrate support 300 is set to be 2.5 times higher than the voltage applied to the grid 200.

In addition, the static electricity adjustment control unit 400 supplies voltage so that the voltage difference between the grid 200 and the substrate support 300 is within a similar preset range, for example, the same, in the static electricity removal mode.

In addition, the static electricity control unit 400 supplies power such as DC, DC pulse, reverse pulse, AC, RF, etc. to the grid 200 and the fingerboard support 300. When supplying voltage in the form of a pulse, the grid ( By supplying voltage so that the 200) and the substrate support 300 synchronize with each other, the efficiency of electrostatic injection and removal can be increased.

In addition, the density of ions and electrons may change depending on changes in the gas flow rate, vacuum degree, pumping speed, etc. in the vacuum chamber (C), so fine control of the density is not possible with direct current power, so the static electricity control control unit 400 is grid-controlled. By controlling the electrostatic voltage more accurately by adjusting the pulse on / off period or polarity of the pulse-type power applied to (200) and the substrate support 300, overshooting on the substrate 10 is prevented. You can prevent it from happening.

That is, when a bias voltage is supplied to the substrate support 300, the charged particles passing through the grid 200 are accelerated toward the substrate 10 by electrical attraction, and the charged particles accelerated toward the substrate 10 are toward the substrate 10. The static electricity is charged or the static electricity formed on the substrate 10 is neutralized.

When removing static electricity using electrons, since the moving speed of electrons is faster than that of positive ions, a negative overcharge phenomenon, that is, excessive static electricity charging, may occur in the insulating thin film on the surface of the substrate 10. . Accordingly, the static electricity control control unit 400 may increase or decrease the bias voltage and supply it to the substrate support 300 in a stepwise manner.

In addition, when electrostatic electricity is injected, the electrostatic control control unit 400 adjusts the voltage level of the voltage supplied to the grid 200 or the substrate support 300 in a certain time unit (several seconds) or stops the voltage supply at a certain interval (interval). ) By setting the automatic neutralization time, it is possible to prevent overcharge on the surface without affecting the nano-sized ultrafine pattern formed on the surface of the substrate 10.

Next, the operation of the static electricity control device of the semiconductor processing system configured as described above will be described with reference to FIG. 8.

First, the substrate 10 on which an insulating film is formed is placed on the upper surface of the substrate support 300 provided in the vacuum chamber C. At this time, the insulating film formed on the surface of the substrate 10 is made of materials such as SiO ₂ , Si ₃ N ₄ , Poly-si, and doped oxide using plasma or atomic layer deposition, and has a thickness of It can vary from 10 nm to 200 nm.

Next, the static electricity control control unit 400 calculates the process gas free stroke distance corresponding to the environmental conditions of the vacuum chamber using Equation 1 (ST100). At this time, various information including temperature, pressure, and process gas molecule size for calculating the process gas free stroke distance can be input in advance by the administrator.

In addition, the static electricity control control unit 400 controls the distance control unit 500 to adjust the grid 200 so that the distance between the grid 200 and the substrate 10 is within 4 times the process gas free stroke distance calculated in the ST100 step. ) or the position of at least one of the substrate supports 300 is adjusted upward or downward (ST200).

In the above state, the static electricity control unit 400 sets a vacuum environment by supplying process gas under preset environmental conditions into the vacuum chamber (C).

In addition, the static electricity control unit 400 generates VUV through the charged particle generation unit 100 and generates charged particles such as positive ions and electrons through a reaction between the VUV and the process gas. Typically, the ion density by VUV is determined by pressure. Although there is a lot of variation, it is approximately 10 ³ to 10 ⁴ /cm ² , whereas the capacity of static electricity required for the substrate 10 is approximately 10 ⁸ to 10 ⁹ cm ² , and a lot of process time is required for electrostatic injection. The process time can be reduced by additionally using a line beam-shaped ion beam using plasma to increase the ion density to 10 ⁶ ~ 10 ⁷ cm ² . As shown in FIG. 4 (A), when a line-shaped beam is emitted from the side of the vacuum chamber (C), active species (radicals) with chemical properties are not generated in the vacuum chamber (C), so the substrate 10 It is possible to perform the electrostatic injection process without damaging the material, and as the process time is shortened, the time that VUV is in contact with the insulating film can be minimized, which can reduce changes in the insulating properties of the insulating film and improve productivity. .

In the above state, when the electrostatic injection mode is set by the manager (ST300), the static electricity control control unit 400 applies a preset voltage to the grid 200 and the substrate support 300, but also applies the voltage to the substrate support 300. The bias voltage is supplied to be more than twice as high as the voltage applied to the grid 200 (ST400). At this time, the voltage applied to the grid 200 is set higher than the voltage applied to the grid 200 in the static electricity removal mode, and the voltage in the form of a pulse can be supplied to at least one of the grid 200 and the substrate support 300.

In addition, in the ST300 step, the manager sets the electrostatic voltage to be injected into the substrate 10, and the electrostatic control control unit 400 stores the grid 200 and the substrate support 300 to correspond to the electrostatic voltage required by the manager. ), and the corresponding power is supplied to the grid 200 and the substrate support 300 accordingly.

That is, in a state where the distance between the grid 200 and the substrate support 300 is within 4 times the free stroke distance of the process gas, the charged particles generated in the charged particle generator 100 are generated by the voltage of the grid 200. The charged particles selectively pass through the microholes and move toward the substrate 10, and are emitted at a higher density toward the substrate 10 by the high voltage applied to the substrate support 300.

Meanwhile, when the distance between the grid 200 and the substrate support 300 is adjusted to within 4 times the free stroke distance of the process gas (ST200), and the static electricity removal mode is set by the manager (ST500), the static electricity control unit 400 ) applies a preset voltage to the grid 200 and the substrate support 300, and sets the voltage applied to the grid 200 and the bias voltage applied to the substrate support 300 to be the same or within a similar range (ST600) ). Here, a voltage in the form of a pulse may be supplied to at least one of the grid 200 and the substrate support 300.

At this time, in the ST500 step, the manager sets the static electricity removal voltage of the substrate 10, and the static electricity control control unit 400 uses the previously stored grid 200 and the substrate support 300 to correspond to the static electricity removal voltage required by the manager. ), and the corresponding power is supplied to the grid 200 and the substrate support 300 accordingly.

In other words, removing static electricity from the surface of the substrate is the same as during the electrostatic injection process, but the static electricity embedded inside the multilayer film of the substrate 10 causes VUV of 100 nm to 200 nm, which has an energy greater than the band gap of each insulating film, to penetrate the multilayer film. As it passes through, static electricity is separated into pairs of holes and electrons to neutralize static electricity, while static electricity on the top of the substrate 10 is neutralized using electrons and ions formed by VUV, electron beam, and ion beam. For example, the VUV energy in the 120 nm wavelength band is 10.33 eV, the silicon energy is 1.1 eV, and the SiO ₂ energy is 9 to 10 eV.

Meanwhile, in the present invention, when the grid 200 and the substrate support 300 have a multi-zone structure, the static electricity control unit 400 injects and removes static electricity into each area of the grid 200 and the substrate support 300. By supplying corresponding different voltages, it can be controlled to inject static electricity into a certain part of the substrate 10 and remove static electricity from another part of the substrate 10.

Claims

A static electricity control device for a semiconductor processing system that injects static electricity onto a substrate placed in a vacuum chamber or removes static electricity formed on the substrate, comprising:

A charged particle generator disposed on the upper side of the vacuum chamber and generating charged particles including positive ions and electrons by generating VUV (Vacuum Ultraviolet Ray) and reacting the VUV with the process gas inside the vacuum chamber;

A grid disposed below the charged particle generator and provided with a plurality of holes that selectively allow charged particles to pass downward depending on the input voltage,

A substrate supporter disposed below the grid, on which the substrate is positioned, and guiding charged particles passing through the grid to the substrate at a preset density according to an input bias voltage;

A static electricity control control unit that supplies pulse-shaped voltage to at least one of the grid and the substrate support to control static electricity of the substrate,

A static electricity control device for a semiconductor processing system in which the grid and the substrate support are arranged to have a separation distance of less than 4 times the free stroke distance of the process gas according to the environmental conditions of the vacuum chamber.
According to paragraph 1,

The static electricity control control unit,

In the electrostatic injection mode, the bias voltage applied to the substrate support is applied to be higher than the voltage applied to the grid by a certain level, and in the static electricity removal mode, the voltage applied to the grid and the bias voltage applied to the substrate support are set to be within a similar range. A static electricity control device for the semiconductor processing system that applies it.
According to paragraph 2,

The static electricity control control unit,

A static electricity control device for a semiconductor processing system that adjusts the voltage level by adjusting the pulse period applied to the grid and the fingerboard support.
According to paragraph 1,

The charged particle generator,

An electrostatic control device in a semiconductor processing system comprising one or more VUV lamps that emit VUV.
According to paragraph 4,

Below the VUV lamp,

It is additionally equipped with a beam generator that emits a line-shaped ion beam through the side of the vacuum chamber, increasing the charged particle density by simultaneously generating charged particles by the reaction of VUV and the process gas, and charged particles by the reaction of the ion beam and the process gas. A static electricity control device for semiconductor processing systems.
According to paragraph 1,

The charged particle generator is a semiconductor device that includes a plasma generator that generates plasma and a separator that transmits only VUV below the plasma generator, and generates charged particles by reacting the VUV generated in the plasma generator with the process gas. Electrostatic control devices in process systems.
According to clause 6,

The plasma generator is a static electricity control device for a semiconductor processing system including at least one micro plasma device that generates plasma using a power source in the range of 10 to 200 W in a vacuum environment where the volume of the vacuum chamber is in the range of 500 to 1000 cc.
In clause 7,

The static electricity control control unit,

A static electricity control device in a semiconductor processing system that controls the static electricity of a substrate by controlling at least one of the type of process gas injected into the vacuum chamber of the micro plasma device or the plasma power source.
According to clause 7 or 8,

The plasma generator includes a plurality of micro plasma devices,

The static electricity control unit is a static electricity control device in a semiconductor processing system that controls static electricity of a substrate by individually controlling the type of process gas or plasma power injected into the vacuum chamber of each micro plasma device.
According to paragraph 7 or 8,

The plasma generator includes a plurality of micro plasma devices,

The separation plates are arranged in a one-to-one correspondence with each microplasma device,

The static electricity control unit adjusts the static electricity of the substrate by individually controlling the type of process gas or plasma power injected into the vacuum chamber of each micro plasma device,

A static electricity control device for a semiconductor processing system, wherein each separator plate is additionally provided with lenses having different divergence angles.
According to paragraph 1,

The grid and the substrate support are of a multi-zone type in which multiple regions are electrically separated, and the static electricity control control unit individually supplies voltages of different levels to each region of the grid and the substrate support. A static electricity control device in a semiconductor processing system.
In paragraph 11

The static electricity control unit is a static electricity control device in a semiconductor processing system that supplies voltage to each area of the grid and the substrate support to inject static electricity into a certain part of the substrate and remove static electricity from another part of the substrate.
According to paragraph 1,

The grid includes an upper grid and a lower grid disposed below the upper grid,

The static electricity control unit is a static electricity control device in a semiconductor processing system that supplies voltages of different levels to an upper grid and a lower grid.
According to clause 13,

The diameter of the hole formed in the lower grid is set to be different from the diameter of the hole formed in the upper grid,

The electrostatic control control unit applies a negative voltage of the first level to the lower grid to induce ions between the lower grid and the substrate to the upper grid through the holes in the lower grid, and then applies a negative voltage greater than the first level to the upper grid. A static electricity control device in a semiconductor processing system that controls electrons with a higher density to be emitted toward the substrate through holes in the lower grid by causing ions introduced through the lower grid to collide with the lower surface of the upper grid to generate secondary electrons.
According to any one of claims 1 or 11 or 13,

A static electricity control device for a semiconductor processing system in which the hole opening ratio in the center of the grid is formed to be higher than the hole opening ratio in the surrounding area.
According to paragraph 1,

It is further provided with a distance adjustment unit that moves the grid and the substrate support up and down within the vacuum chamber,

The static electricity control unit is a static electricity control device in a semiconductor processing system that controls the distance adjustment unit to change the position of at least one of the grid or the substrate support to the upper or lower side based on the process gas free stroke distance calculated by the environmental conditions of the vacuum chamber. .
According to paragraph 1,

A static electricity control device for a semiconductor processing system that prevents arc generation by coating or sputtering a film containing carbon, including carbon, CNT, and glassy carbon, on the surface of the grid.
According to paragraph 1,

A semiconductor processing system that prevents arcing by coating or sputtering the surface of the grid with one of silicon oxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), silicon nitride (Si 3 N 4 ), and an oxide-based thin film. Electrostatic control device.